The invention relates to prosthetic devices and methods of forming the same. In particular, the invention relates to a method of forming both transfemoral and transtibial, test or temporary and final, permanent sockets, and an adapter bracket for use therewith. The invention also relates to a method for transferring the alignment of a lock mechanism and/or socket attachment adapter bracket from a test socket to a final socket.
In the known prosthetic devices, the residual limb socket is connected, typically via a lock mechanism, to a prosthetic limb. The prosthetic limb is conventionally secured to an amputee's residual limb stump by securing the prosthetic limb to a rigid socket assembly. This may be done using suction, harnesses, etc. or combinations thereof. It is commonly done through the use of a locking pin. In this technique, the amputee first dons a sock-like liner formed of an elastomer, and which may include a fabric cover. The lower or distal end of the liner is formed of a rigid material, such as urethane, and the locking pin extends from this rigid bottom. These liners are well known in the art. The locking pin is extended through the wall of the socket and a distal adapter mounted within or outside of the socket, and can be locked onto a prosthetic lock mounted to the prosthetic limb to secure the prosthesis. Typically, the lock pin can be released only by moving a pinion gear in a direction parallel to its rotational axis until it disengages from the lock pin, e.g., via a manual release button.
In the conventional fabrication process, an initial design is determined for the prosthesis, perhaps with the aid of computer-aided design and manufacturing (CAD/CAM) systems, and a plaster model of the residual limb is created. Then, a “test socket” is formed on the plaster model. The test socket is placed on the patient and, if the fit of the test socket can be improved, revisions may be made and the process repeated until the desired fit is obtained. At that point, the test socket is filled with molding plaster to create a final plaster model for use in creating the final or permanent socket. Once the molding plaster has cured, the final plaster model is separated from the test socket, typically using a cast saw to cut away the test socket. In any event, the test socket must be cut apart to remove the adapter bracket and lock mechanism, if any, for use in the final socket. A final or permanent socket is then fabricated, either laminated or of the thermoplastic resin type, using the final plaster model. Typically, a vertical alignment transfer jig is relied upon in an attempt to recreate in the final socket the orientation of the adapter bracket relative to the socket found to be desirable in the test socket.